# To flee or wait and see? Response of incubating white-browed scrubwrens to information about danger

## TL;DR

Nesting white-browed scrubwrens use sounds to detect nearby predators but prioritize staying hidden to protect their young rather than fleeing.

## Contribution

This study reveals how incubating birds use acoustic cues to assess predation risk while balancing self-protection with nest crypsis.

## Key findings

- Incubating scrubwrens responded more to danger sounds than control calls but rarely fled.
- Birds looked around more after mobbing calls, possibly to gather more information about the threat.
- Scrubwrens prioritize nest crypsis over immediate escape from predators.

## Abstract

Animals suffer elevated predation risk during reproduction, with nesting parents having to decide whether to flee from nearby predators for their own safety or to stay and thus avoid betraying the nest's location to protect offspring. Gaining information about the source of danger is therefore crucial. From inside a nest, it might be difficult to gather relevant information visually and so acoustic signals and cues become particularly important. However, there has been little investigation of the response of nesting parents to acoustic information about different predation risks. We used a playback experiment to test how incubating female white-browed scrubwrens, Sericornis frontalis—which build extremely cryptic, dome-shaped nests close to the ground—respond to aerial alarm calls (warning of airborne predators), mobbing alarm calls (warning of stationary predators on or above the ground), the footstep sounds of a nest predator on the ground, and control calls of a harmless parrot. We found that incubating scrubwrens responded more to the “danger” treatments compared with the control but, contrary to expectation, rarely fled in response to any of the predatory threats. However, birds looked around more actively (more saccades) after mobbing calls compared with the other playbacks, perhaps because mobbing calls do not indicate the specific location of danger and so additional information gathering is valuable. Incubating scrubwrens can therefore recognize potential danger by sounds, but evaluated risk from within the nest rather than immediately fleeing, suggesting that they prioritize nest crypsis over other anti-predator strategies.

Nesting birds face a tough decision: flee from predators for their own safety or stay hidden to protect their young. This is harder when their view is blocked by nest materials. Incubating white-browed scrubwrens could use sounds to detect danger, including alarm calls and predator footsteps. They looked out more if they cannot tell the predator’s location by sounds, but overall stayed hidden to avoid nest exposure, which may enhance the chance of young survival.